Lifting clamp



Nov.` 18, 1952 G. ROSENBAUM 2,618,505

LIFTING CLAMP Filed May 51, 1951 2 Sl-IEETS--SI-IEET 2 MIM A HIIIIII INVEN TOR. GAD Rage/yawn e www ATTORNEY.

Patented Nov. 18, 1952 UNITED STATES PATENT OFFICE` LIFTING CLAMP Gad Rosenbanm, Detroit, Mich. ApplicationMay'Sl, 19.5111, Serial No. 229,213

, The present invention pertains toA a novel clamp for liftingplates' and similar heavy objects in shops, on construction jobs, and the like. The clamp is of the gravity type wherein the weight of the work piece causes a movable jaw to bind or clamp the piece against an opposite xed jaw.

A serious defect of this type of clamp is that it becomes released as soon as the work piece is Vlowered into contact with the floor or ground,

since the clamping action depends only on the weight of the piece. In handling heavy pieces the Workmen are in constant danger of being injured by the slipping of the piece out of the clamp.

The principal object of this invention is to provide such a clamp wherein a positive clamping pressure is maintained on the work piece when the latter touches the floor or ground. The clamp body is slidably guided on a shackle, and the movement of the shackle operates a pivoted jaw through a link connection. The shackle body is slotted from its lower edge to receive the upper edge of the work piece, and the pivoted and xed jaws extend into this slot. An upward force on the shackle, or relative downward movement of the clamp body, effects a clamping movement of the pivoted jaw.

According to this invention, the lower end of the shackle or a part connected thereto travels downward along the work-receiving slot when the upward pull on the shackle is released. This occurs of course when the work piece engages the floor or ground. At this time the part eX- posed in the slot comes into contact with the upper edge of the work piece and exerts an upward force on the shackle through the weight of duces a clamping action oi the pivoted jaw, with f the result that there is a positive clamping pressure on the work piece although it is in engagement with theloor or ground. Full release is obtained when desired merely by lifting the clamp manually.

' The invention is fully disclosed by way of example in the following description and in the accompanying drawings in which:

Figure 1 is a side elevation of the device, showing the shackle approaching the work piece in the resting position of the latter;

Figure 2 is an end View;

Figure 3 is a section on the line 3 3 of Figvure 2;

7 Claims. (Cl. 4294--4-104)v -the same relative position as with one of the body plates removed;

Figure 5 is an elevation ofanother modicjation, with one of the body plates removed;' jV

Figure 6 is a side elevation thereof, and Figure '7 is a section on the line 1-1 of Figure 5. A

Reference to these views will now be made by use of like characters which are employedNto designate corresponding parts throughout. i;

In Figure 1 the device is shown as having a body consisting of a pair of spaced plates I 4and 2 between which the working parts of the clamp are assembled as will presently be described. From the lower edge of the body, the plates `are slotted upward as indicated by the numeral 3. In one of the lower corners of the body a fixed jaw Ii is secured between the plates by a pairpf rivet head pins 5. The fixed pins passing through the plates at other points are also formed with rivet heads and held by cotter pins 5 and will not be described in detail. Rivets 'l hold the plates together near the upper corners. A guide slot 8 is formed in each plate Iand 2 above the slot 5 and substantially coaxial therewith. A shackle 9 has its lower end receivedibetween the plates I and 2 and between the pins 1. The shackle is guided in the slots 8 by means l`of a headed bolt I!) carried by the shackle' and slidably received inthe slots 8. The head of the bolt lies outside one of the plates, and the other end of the bolt is fitted with a nut II onthe outer side of the other plate. The lower end of the shackle is enlarged at I2 in order to be exposed at the slots 3 when the pin I0 is at the bottom of the slots 8, for a purpose that vwill presently be described. The upper en d of the Ashackle is formed with the usual eye I3'.

In the lower corner of the body, opposite the jaw il is pivotally mounted a movable jaw' I4 on a pivot pin I5. This jaw has a curved serrated face IS extending into the slots 3, while the jaw i has a straight serrated face I1 also exposed' at the slots 3.

The outward end of the jaw I4 is straddled by' a pair of similar links I8 pivotally attached to the end by a pin I9 which, however, does notpass through the plates I and 2. The opposite ends of these links straddle the lower end of the shackle 9 and are pivotally mounted on the sliding pin Iii. When the pin Il! is in the lower end of the slots 8, the links I8 space the face I6 of the jaw I4 from the face Il of the jaw ft, anda work .drops to the bottom of the slots 8. .upper ends .of .the links I8 are enlarged to form la ,downwafdl-y facing shoulder 2| which obviously it rides upward relatively to the slots 8, carrying the pin IIl and the upper ends of the links I8 upward in the slots to turn the jaw I4 toward the jaw 4, whereby to clamp the member 20 between the jaws.

As previously indicated, the present lifting clamps of this character release the work piece when the latter is brought down to the floor, since the clamping effect is derived from the gravity pull of the work piece. With the clamp released and the work piece in vertical position although resting on the floor, the piece is not held securely and the handlers are in danger of being injured if a heavy plate slips out of the clamp. This condition does not occur in the clamp described herein. When the work piece 20 engages the floor and the pull is taken off the shackle, the parts ride downward along the slots 8, 'bringing the enlarged lower end I2 of the shackle pacross .the slots 3 until it engages the upper end of the work lpiece. A slight .upwardgpressure is thereby .exerted on the .shackleand as-pueviously described,

,this produces aclampinggaction of -the jaws on the-work piece. .In another- .sense the pin. I does not .quite .reach the bottom of the slots so that `the jaw I4 is not-brought to its full open position. The clamp is fully released by manually lliftingthe ,body vI v2.

Themodication showninFigure 4 differs from the Ipreyious .construction only in the particulars .thatwill now .be.descrbed. The .shackle S does nothave its lower .end .I'2 .enlarged and does not ,become .exposed at the slot '.3' when the pin Iii Instead, the

movesdownward along the slots .3 as the pin .IIJ .approaches lthe bottom of the slots 8. This .shoulder yengages the `work piece when thepull is taken off the shackle, An upward .pressure on l.the .slidingpin is thereby exerted, as described in .connection with `the pin Il), to maintain clamping pressure `on .the jaw I4' through the links I A8'. As in the previous construction, this pressure isreleased when desired by manually .lifting the body of the clamp.

.In the rst .described construction the movement of .the enlargement I2 on the upper edge .of the work piece 2D during swivelling of the .shackle 9 may be undesirable. Such scraping .isavoided by the shoulder 2| of Figure .4 which `vprojects beyond the lower end of the shackle 9.

YIn Figure .5 is illustrated a form of the invention .adapted toa somewhat different connection .from theshackle to the movable cam. The body of the device, as previously, consists of a pair of plates 2 suitably secured .together and having a work-receiving slot .22 extending from the lower Yedge as previously described. At one side of the slot isa fixed jaw 23, and at the opposite side is a pivoted jaw 24 mounted on a suitable .pin `2,5.

Somewhat above the slot 22 is -another pivot Din 2.6 .on which ismounted a rock-er .arm ,27. The

shackle 28 is pivotally attached to one end .of the rockei-.armby a pin 29. From the lother end of .the rocker arm extends a pair of links 3i) held thereto by a pin 3I and joined to .opposite sides of the jaw 24 by another pivot pin .32.

At the upper end of the arm 2l is an enlarge- :ment 33, similar to the enlargement ZI of Figure 4, which extends .across the upper end of .the slot 22 when tension is taken off the shackle. The .operation of this device is as described in connection with Figure 4. The difference lies in `theworking.connection .from the shackle to the pivoted jaw, the link being guided by a rocker arm rather than by the slot of the previously described constructions. The plates 2 are held together by suitably located rivets 34 as well as the fixed pivot pins 25 and 29.

A similar light clamping action of either device is obtainable in lifting the work piece from a horizontal position, in which the work-receiving slot lies on a horizontal axis while the clamp is being applied. The shackle is merely pushed by hand until the member exposed in the slot 2| engages the work piece with some pressure to actuate the pivoted jaw to a clamping position as Ipreviously set forth.

Although specific embodiments of the invention .have been illustrated and described, it will .be understood that various alterations in the details of construction may be made without departing Vfrom the scope of the invention as indicated by the appended claims.

Whatl claim is.:

1.. .A lifting .clamp comprising abodyhaving a workfreceiving slot extending from one edge thereof, va jaw carried by said bodyand extending into said slot from one side thereof, another jaw eccentrica'lly pivoted to said body and extending into said slot at the other side, a shackle slidably connected to said body, an articulated connection between said shackle and pivoted jaw, for tightening said pivoted jaw by an outward pull .on said shackle, and means movable vertically with said shackle and movable .to a position between the ends .of said slot on the clamp-.releasing movement .of said shackle, for engagement with a work piece in said slot.

2. A lifting clamp comprising a bodyhaving a .work-receiving slot extending from one edge thereof, a jaw carried by said body and .extending into said slot from one side thereof, another jaw eccentrically pivoted to said body and extending into said slot at the .other side, a shackle having -a slidable pin-.and-slot connection to said body, .an articulated connection between said shackle andpivoted jaw, for tightening said pivoted jaw by .an outward pull on said shackle, and means movable vertically with said shackle and movable to a position between the ends of said slot on the clamp-releasing movement of said shackle, for .engagement with a work piece in said slot.

3. A lifting clamp comprising a body having a work-receiving slot extending from one edge thereof, a jaw carried .by said body and extending into said slot from one side thereof, another jaw eccentrically pivoted `to said body and extending into said slot at the other side, a shackle slidably connected to said body, an articulated connection between said shackle and pivoted jaw, for tightening said pivoted jaw by an outward pull on said shackle, the end `of said `connection at said shackle having a portion movable to a position betweenthe ends of .said slot on the clamp-releasing movement .of said shackle, for engagement with a work piece in said slot.

4. A lifting clamp comprising a body having a work-receiving slot extending from one edge thereof, a jawcarried by said body and extending vinto said slot from one side thereof, another jaw eccentricallypivoted to said body and extending into said slot at the other side, a shackle having a slidable pin-and-slot connection to said body, an articulated connection between said shackle and pivoted jaw, for tightening said pivoted jaw by an outward pull on said shackle, the' end of said connection at said shackle having a' portion movable to a position between the ends of said slot B 0n the clamp-releasing movement of said shackle, for engagement with a work piece in said slot.

5. A lifting clamp comprising a body having a Work-receiving slot extending from one edge thereof, a jaw carried by said body and extending into said slot from one side thereof, another jaw eccentrically pivoted to said body and extending nto said slot at the other side, a shackle slidably connected to said body, an articulated linkage having pivotal connections to said shackle and pivoted jaw, for tightening said pivoted jaw by an outward pull on said shackle, the inner end of said shackle being movable to a position between the ends of said slot on the clamp-releasing movement of said shackle, for engagement'with a work piece in said slot.

6. A lifting clamp comprising a body having a work-receiving slot extending from one edge thereof, a jaw carried by said body and extending into said slot from one side thereof, another jaw eccentrically pivoted to-said body and extending into said slot at the other side, a shackle having a slidable pin-and-slot connection to said body, an articulated linkage having pivotal connection to said shackle and pivoted jaw, for tightening said pivoted jaw by an outward pull on said shackle, the inner end of said shackle being movable to a position between the ends of said slot on the clamp-releasing movement of said shackle, for engagement with a work piece in said slot.

7. A lifting clamp comprising a body having a work-receiving slot extending from one edge thereof, a jaw carried by said body and extending into said slot from one side thereof, another jaw eccentrically pivcted to said body and extending into said slot at the other side, a rocker arm pivoted to said body near the upper end of said slot, a link extending from said pivoted jaw to one end of said rocker arm, a shackle pivoted to the other end of said rocker arm, for tightening said pivoted jaw by an upward pull on said shackle, the last named end of said rocker arm having a portion movable to a position between the ends of said slot on the clamp-releasing movement of said shackle, for engagement with a work piece in said slot.

GAD ROSENBAUM.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,510,176 Knight Sept. 30, 1924 1,760,885 Prelesnik June 3, 1930 2,446,610 Renfroe Aug. 10, 1948 

